What the research tells us about plug-in air fresheners, synthetic fragrances, and the canine nervous system
We often think of fragrance as something pleasant. A home that smells like lavender, fresh linen, or citrus may seem clean, inviting, and relaxing to us. But have you ever considered what those fragrances might be like for your dog?
Dogs experience the world primarily through their sense of smell. Their olfactory system is extraordinarily sensitive, allowing them to detect and distinguish odors at concentrations far below what humans can perceive. Smell provides dogs with essential information about their environment, other animals, people, and the world around them.
Yet many dogs spend their days surrounded by artificial fragrances from plug-in air fresheners, scented candles, laundry detergents, fabric sprays, and household cleaning products. These products can continuously introduce fragrance chemicals into the air, often in enclosed spaces where dogs have little opportunity to escape them.
As we learn more about the relationship between environmental exposures, physiological regulation, and behavior, it's worth considering whether these products belong in our dogs' living environments.
What's Actually in Artificial Fragrances?
The word fragrance on a product label can represent a complex mixture of chemical compounds. Depending on the formulation, these may include synthetic aroma chemicals, solvents, stabilizers, and other ingredients used to create and maintain a particular scent.
Some fragrance-related chemicals have been identified as potential endocrine disruptors. Endocrine-disrupting chemicals are substances that can interfere with the body's hormonal signaling systems, potentially affecting processes such as reproduction, metabolism, development, and stress physiology.
One group of chemicals that has received considerable scientific attention is phthalates. Certain phthalates have been used in fragranced products, and some have demonstrated endocrine-disrupting effects in experimental research. However, not all phthalates have identical properties, and not all fragrance products contain them.
A 2012 study published in Environmental Health Perspectives examined a variety of consumer products for chemicals associated with endocrine disruption and asthma. Researchers identified numerous potentially concerning compounds, including chemicals in fragranced products such as air fresheners and dryer sheets. Many were not disclosed individually on product labels.
This doesn't mean every artificial fragrance will cause hormonal disruption. It does mean that fragranced household products can be sources of chemical exposure that consumers may not fully understand.
Plug-In Air Fresheners and Indoor Air Quality
Plug-in air fresheners are particularly interesting because they release fragrance into the environment over extended periods. Unlike a cleaning product that is applied and then removed, a plug-in device is designed to maintain a continuous scent.
Many fragrance formulations release volatile organic compounds, or VOCs. These are chemicals that evaporate into the air at ordinary indoor temperatures.
Not all VOCs are harmful at typical exposure levels, but some can contribute to indoor air pollution. Certain fragrance ingredients, particularly compounds called terpenes, can also react with ozone in the air to create additional pollutants.
Research has demonstrated that these reactions can produce substances such as formaldehyde and ultrafine airborne particles. Depending on the concentration and exposure conditions, these pollutants may contribute to respiratory or sensory irritation.
A 2014 study published in Environment International specifically examined emissions from a plug-in air freshener. Researchers found that reactions between emitted fragrance compounds and ozone could generate secondary pollutants, including formaldehyde.
The U.S. Environmental Protection Agency also recognizes that certain fragranced household products can contribute to indoor particle formation through chemical reactions.
For a dog spending much of the day inside the home, these exposures are worth considering, particularly if the dog has respiratory sensitivities or other health concerns.
A Dog's Sense of Smell Changes the Conversation
Dogs possess a remarkable olfactory system. Their ability to detect and discriminate odors is central to how they navigate their environment, communicate, and gather information.
When a dog enters a room, they aren't simply noticing whether it smells pleasant or unpleasant. They are gathering information about who has been there, what has happened, and what might be present.
Now imagine introducing a continuous artificial fragrance into that environment.
A plug-in air freshener may be barely noticeable to us after a few minutes because we become accustomed to the smell. But our reduced awareness doesn't mean the fragrance chemicals have disappeared from the air.
Dogs can detect many odors at much lower concentrations than humans, although their sensitivity varies considerably depending on the substance. Importantly, this doesn't automatically mean that a fragrance is distressing or toxic to a dog simply because they can detect it.
What it does raise is a reasonable question: Are we considering our dogs' sensory experience when we choose how our homes smell?
Dogs have no control over the scented products we use. They cannot unplug an air freshener, change the laundry detergent, or ask us to stop spraying fragrance on the furniture where they sleep. Providing a comfortable environment means considering not only what we see and hear, but also what our dogs are continually smelling.
Could Fragrances Influence a Dog's Nervous System?
The autonomic nervous system helps regulate essential physiological functions, including heart rate, breathing, digestion, and responses to stress.
A dog's ability to recover from frightening or overwhelming experiences depends on multiple interacting processes involving the nervous system, endocrine system, and environment.
We know that environmental conditions can influence stress and behavior. Noise, unpredictable activity, uncomfortable temperatures, social pressure, and other stressors may affect a dog's capacity to rest and recover.
Could persistent artificial fragrances contribute to that overall environmental burden?
It's a question worth investigating, but one that requires scientific caution. At present, there is insufficient direct research demonstrating that ordinary exposure to plug-in air fresheners causes autonomic dysregulation, chronic anxiety, or behavioral reactivity in dogs.
We also cannot assume that a chemical identified as an endocrine disruptor necessarily causes measurable hormonal changes in every animal exposed to a household product containing it. The actual risk depends on the substance, concentration, duration of exposure, and individual susceptibility.
However, we do know that some fragranced products release chemicals capable of affecting indoor air quality, and that certain fragrance-related compounds have demonstrated biological effects under experimental conditions.
For dogs already struggling with environmental sensitivities, reducing unnecessary exposures may be a reasonable part of creating a more comfortable living environment.
Why This Matters for Fearful, Anxious, and Reactive Dogs
When working with dogs who experience chronic anxiety, fear, or behavioral reactivity, it's important to consider the whole animal and the environment in which they live. Behavior does not occur in isolation.
A dog's physical comfort, sleep quality, health, relationships, daily experiences, and opportunities for recovery all contribute to their overall well-being.
Sometimes we focus so heavily on what happens during a walk, when guests arrive, or when another dog appears that we overlook the conditions the dog experiences during the rest of the day.
Is the home quiet enough for restorative sleep? Does the dog have a comfortable place to rest without interruption? Are there persistent noises, strong odors, or other environmental conditions that might be uncomfortable?
Not every dog will be bothered by the same things, and we shouldn't assume that artificial fragrance is responsible for a dog's behavioral difficulties.
But reducing unnecessary environmental exposures is a relatively simple step that may help us better understand an individual dog's needs.
Our goal is not simply to change a dog's outward behavior. It is to support the physical and emotional conditions that allow the dog to feel comfortable, recover from stress, and engage with the world.
What About Essential Oils and Natural Fragrances?
It's tempting to assume that replacing synthetic fragrances with essential oils is a healthier solution.
Unfortunately, natural doesn't necessarily mean safe.
Essential oils are concentrated mixtures of biologically active compounds. Some can cause irritation or toxicity in animals, depending on the particular oil, concentration, route of exposure, and species.
Diffusing essential oils also introduces volatile compounds into indoor air. Certain naturally occurring fragrance chemicals can participate in the same types of indoor chemical reactions as synthetic fragrance ingredients.
For this reason, replacing plug-in air fresheners with essential-oil diffusers isn't automatically a safer choice for dogs. A fragrance-free environment is different from an environment scented with natural products.
Creating a Healthier Indoor Environment for Your Dog
Fortunately, reducing unnecessary fragrance exposure doesn't have to be complicated.
Start by unplugging continuous air fresheners and limiting the use of scented sprays, candles, and fragrance diffusers. Consider fragrance-free laundry detergents, especially for bedding and blankets your dog uses regularly.
Choose cleaning products based on their actual cleaning function rather than their scent, and follow product directions carefully. When possible, improve ventilation and address the source of unpleasant odors instead of covering them with additional fragrance.
It's also worth remembering that unscented and fragrance-free aren't always interchangeable. Some products labeled unscented contain masking fragrances designed to neutralize other odors.
When making changes, observe your individual dog. Pay attention to their comfort, rest, respiratory health, and behavior, but avoid assuming that any improvement or deterioration must be caused by fragrance exposure alone.
If your dog develops coughing, breathing difficulties, unusual lethargy, or other concerning symptoms, consult your veterinarian.
The Bigger Picture: Respecting the Dog's Sensory World
One of the most important things we can do for our dogs is recognize that they experience the world differently than we do.
We often organize our homes around human preferences. We choose the lighting, the sounds, the cleaning products, and the fragrances that surround us. Our dogs live within those choices.
Understanding canine behavior requires us to consider the dog's perspective, including sensory experiences we may not fully appreciate. We don't need to conclude that every artificial fragrance is dangerous or that all scented products cause behavioral problems. The science doesn't support those sweeping claims.
But there is enough evidence about certain fragrance chemicals, indoor air pollution, and individual sensitivities to justify being thoughtful about unnecessary exposure. A comfortable home doesn't need to smell like artificial flowers, ocean breezes, or freshly washed linen.
Sometimes the most considerate choice we can make for our dogs is simply to let the air be air.
References and Further Reading
Dodson, R. E., et al. (2012). Endocrine Disruptors and Asthma-Associated Chemicals in Consumer Products. Environmental Health Perspectives, 120(7), 935–943.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3404651/
Ozone-Initiated VOC and Particle Emissions from a Cleaning Agent and an Air Freshener (2014). Environment International.
https://pubmed.ncbi.nlm.nih.gov/24769411/
Ashcroft, et al. (2024). Synthetic Endocrine Disruptors in Fragranced Products. Endocrines.
https://www.mdpi.com/2673-396X/5/3/27
U.S. Environmental Protection Agency. Sources of Indoor Particulate Matter.
https://www.epa.gov/indoor-air-quality-iaq/sources-indoor-particulate-matter-pm
This article is intended for educational purposes. Research on fragrance-related chemical exposure is developing, and findings from human, laboratory, or environmental studies should not automatically be interpreted as evidence of specific health or behavioral effects in dogs. For concerns about an individual dog's health or possible chemical exposure, consult a veterinarian.